Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden and does well: it discloses the artifacts produced, the interactive studio, live material pricing, downloadable formats, and an explicit cost ('1 credit per call'). It omits persistence/latency or limits on regenerating, so it is strong but not exhaustive.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with what it does and what it returns, then optionals, then the cost note. Dense but every clause maps to a real capability or parameter; the output-format enumeration (IFC/CSV/DXF/STL) is slightly listy but still earns its place as an integration signal.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema and 15 params with one nested object, so the description must do heavy lifting; it covers the return artifacts, cost, and the high-value inputs well. The gap is the unexplained region/site_lat/site_lon/title params and no statement on error or fallback behavior, so an agent could still call it correctly but not optimally.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 7% (just brief), so the description must compensate and does for most inputs: it explains budget_usd semantics (live material prices), layout provenance (plan.json from the studio), rooms syntax ({bedroom:3,...}), roof enum values, structure enum values, and area/floor/height params. It leaves title, region, site_lat, and site_lon unexplained, so it falls short of fully covering 15 params.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a concrete verb+resource ('describe a building... generates a laid-out floor plan per storey, 3D model, room schedule, energy/budget numbers, build guide'). The specific artifact list (DXF/SVG, STL, IFC, CSV) clearly separates it from siblings like arch_review or cad_build without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes between two modes: give budget_usd to size to a budget, or layout (plan.json exported from the studio) to rebuild an edited design. This is clear 'when-to-use-which-input' guidance, but it never names when to prefer arch_design over adjacent siblings like arch_review or cad_* tools, so it stops short of a full 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.